Using gpg with sylpheed?

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

Is anyone successfully using gpg with sylpheed 2.2.0?  Any time I try 
to sign something, it says 

        (sylpheed:821): Sylpheed-WARNING **: pgp_sign(): signing failed: User

I've groveled through sylpheed, gpgme, and libgpg-error and haven't even 
figured out what the message means...  

'ls' shows that my gpg configuration file is being read, but none of my 
other files, including specifically my keyring, are being touched.  I'm 
asking here because I see no mention of any such problems in the 
sylpheed archives; I'm wondering if it's NetBSD- or pkgsrc-specific.

                --Steven M. Bellovin, http://www.cs.columbia.edu/~smb